nanog mailing list archives

Re: What is multihoming was (design of a real routing v. endpoint id seperation)


From: Robert Bonomi <bonomi () mail r-bonomi com>
Date: Tue, 25 Oct 2005 07:56:29 -0500 (CDT)


From owner-nanog () merit edu  Mon Oct 24 15:33:02 2005
Date: Mon, 24 Oct 2005 13:31:17 -0700
Subject: Re: What is multihoming was (design of a real routing v. endpoint id
 seperation)

Stephen Sprunk wrote:
[snip]

Other people use this term in very different ways. To some people
it means using having multiple IP addresses bound to a single
network interface. To others it means multiple websites on one
server.


That is virtual hosting in a NANOG context.  Some undereducated MCSEs 
might call it multihoming, but let's not endorse that here.

Unfortunately, this is a common and "standards blessed" way to refer to
any host with multiple interfaces/addresses (real or virtual). For example,
from the "Terminology" section, 1.1.3, of RFC1122, "Requirements for
Internet Hosts -- Communication Layers," says,

          Multihomed
               A host is said to be multihomed if it has multiple IP
               addresses.  For a discussion of multihoming, see Section
               3.3.4 below.


*sigh*  Multi-homing simply means 'having external connections to more than 
one network' -- be it a network with multiple, disjoint, ingress/egress paths,
or a host with interfaces (real or virtual) on distinct LAN subnets (even if
those subnets are agregated into a single net somewhere upstream.

A host with multiple adresses utilizing the _same_ netblock/netmask _should_
_not_ be called multi-homed (because there is only one path to that host), it
is simply a single-homed host with multiple identities.  might be called
"poly-ip-any" or some such.  <grin>




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